Markús Skeggjason (Mark) was the son of Skeggi Bjarnason and possibly a brother of the poet Þórarinn Skeggjason (ÞSkegg). He was lawspeaker in Iceland from 1084 until his death on 15 October 1107. In Íslendingabók (Íslb, ÍF 1, 22) he is named as an important informant for Ari Þorgilsson about the lives of the earlier lawspeakers in Iceland. He had gained this information from his brother, father and grandfather. Markús appears to have had close ties to the Church: during his time as lawspeaker, and with his guidance, Gizurr Ísleifsson, bishop of Skálholt (1081-1118), established the Icel. tithe laws (ÍF 1, 22). Markús was among the most respected poets in the canon of the C13th and he is cited often in SnE and TGT (see below).

In Skáldatal, Markús is associated with S. Knútr Sveinsson of Denmark (d. 1086), Eiríkr inn góði ‘the Good’ Sveinsson of Denmark (d. 1103), and Ingi Steinkelsson of Sweden (d. 1110) (SnE 1848-87, III, 252, 258, 260, 267, 271, 283, see also 348-53). An extended hrynhent poem about Eiríkr (Mark Eirdr), composed after his death in 1103, and one helmingr about ‘Sveinn’s brother’, probably S. Knútr (Mark KnútdrIII), survive, alongside one helmingr and a couplet from a possible drápa about Christ (Mark KristdrIII) and two lvv. (Mark Lv 1-2III). Aside from Eirdr, all of Markús’s extant poetry is transmitted in SnE or TGT, and it has been edited in SkP III.